Electric relay



Feb. 17. 1925.

N. W. M LACHLAN ELECTRI C RELAY 2 Sheets-Sheet 1 Filed Dec. 13. 1921 animator,

NORMA W. MLAcH LAN 1 his Qbl ozmeq l y Patented Feb. 17, 1925.

UNITED STATES PATENT OFFICE.

NORMAN WILLIAM MCLACHLAN, OF NEWCASTLE-ONTYNE, ENGLAND, ASSIGNOR TO RADIO CORPORATION OF AMERICA, A CORPORATION OF DELAWARE.

ELECTRIC RELAY.

Application filed December 13, 1921.

To all whom it may concern:

Be it known that I, NORMAN lVILLIAM MGLAGHLAN, a British subject, of 8 estwood Avenue, Heaton, Newcastle-on-Tyne, England, have invented certain new and useful Improvements in Electric Relays, of

which the following is a specification, accompanied by drawings.

The object of this invention is to provide a. relay whereby consideratle force can be obtained directly from a. small current with out the employment of contacts for open ing and closing an auxiliary circuit.

According to this invention I arrange a band carrying a number of steel or iron shoes around part of the periphery of an iron or steel drum having in it an annular groove in which a coil of wire is wound. The ends of the coil are connected to slip rings through which current can be supplied to the coil, and means are provided for rotating the drum at a constant speed. lVhcn therefore a current traverses the coil, the drum becomes an electromagnet and the band and shoes are attached thereto and tend to travel round with the drum. The force tending thus to carry the band and the shoes round may be used for various purposes, for exan'iple, working a Morse or other inke-r, signalling keys, etc. The band may be connected to a bell crank lever which is normally held against a stop by a spring which is pulled away from the stop when the drum becomes magnetized. The pull on the band increases more rapidly than the magnetizing force or the ampere turns, and it is therefore convenient in some cases to provide a second coil on the drum with its own pair of slip rings and to pass a polarizing current through this second winding so that a large variation in the pull on the band may be obtained with a given current through the operating or relay winding. A permanent magnet may be used instead of the polarizing winding.

In place of shoes upon a single band, a ring formed in two parts held together and having the ends remote from the hinge connected together by a spring may be used.

Several of such relays may be joined in cascade, the relay windings of the various relays being connected together.

My invention is illustrated by the accompanying drawing, Figure 1 of which is an Serial No. 522,172.

elevation and Figure 2 a sectional plan of a relay constructed in accordance therewith. Figures 3 and 4 are diagrams showing methods of employing such a relay.

Referring to Figures 1 and 2, A is a soft iron shaft carrying two windings or coils B B the ends of which are connected to two pairs of slip rings C, O and C C respectively, through which current can be led to the coils. The coils are enclosed in a drum formed of two flanged collars D on the shaft. The edges of the flanges on the collars do not quite meet so that an air gap is left between them and they are tapered in order to increase the magnetic reluctance of the path from collar to collar. Thus the magnetic flux is constrained to pass through the band and thereby the force acting on the shoes on the band is increased. Round a portion of the periphery of the flanges or drum passes a band E having on it shoes F. To the ends of this band are attached springs G G which hold it in position. The extent of the periphery of the drum with which the band is in contact may be varied by an adjustable arm R to which the spring G is attached. The tension of the two springs may be regulated by means of screws g. The band is thus held in position longitudinally and transverse movement may be prevented by arranging on the inside of the shoes small pins which project through the gap between the flanges of the collars D. The shaft A is constantly rotated in the direction of the arrow (Figurel) by means of an electric motor connected to the coupling Q. There is in consequence a tendency for the band to be carried round owing to the friction between 'the shoes and the collars, but this is counteracted by the spring G lVhen, however, a current is passed through one of the coils the drum becomes magnetized and attracts the shoes on the band which is consequently ulled round extending the spring G. l Vhen the current stops this spring pulls the hand back to its normal position.

l igures l and 2 show how such a relay may be employed to record telegraphic signals, the signal current being supplied through collector brushes 0 to the slip rin C C To the band is attached one arm of a bell crank lever L which can be turned on its pivot between two stops N. The other arm of the lever carries a siphon 7L dipping into an inkpot. The siphon is thus moved over a travelling tape T. In order to ob-' tain a positive or negative magnetic bias of the parts of the drum, that is, to polarize them, one of the coils B on the drum may be connected to a local battery 0.

Figures 3 and l show how two such relays may be employed to actuate a signalling key.

In Fig. 3 d, d, are two drums, rotated in opposite directions and having their bands E connected at one end to springs and at the other ends to two sides of a: lever S. The coils or windings B of both drums may be connected in series as also may t-le coils B When-there is no current in tli'e coils E the frictional forces on the two bands balance out'on lever S, any tendency to unbalanced action being corrected by adjusting the springs. The relay windings orcoils B B are connected so that the effect of increasein current in one of them is to increase the ampere turns on the corresponding' drum, and, consequently, the magnet-i2 ing'force on the band E 'coacting with the drum, whereas the effect of the simultaneous increase in current in the other winding is to decrease the ampere turns on the second drum. Thus the lever is pulled 011 to one contact or the other according to the direc' tion of the current. By making, breaking and reversing the current in sequence, the lever will rock. Thus the lever can be operated by a VVheatstone transmitter.

An alternative scheme is illustrated in Figure l. The two bands e (not necessarily flexible) which rotate in opposite directions are coaxial and coupled by a suitable piece of brass'or aluminum. One band is connected directly tothe key lever S; The windings are connected so that the ampere turns on one drum increases when the ampere turns on the other decreases.

The advantage of the system of Figure 4f posite directions and there is no current in the relay windings. 1

Having described my invention, what I claim is:

1. In an electric relay, the combination of a rotatable drum of magnetic material, a body of magnetic material in frictional engagement with said drum, means for magnetizing said members for varying the fricmagnetic material in frictional engagement.

therewith and extending substantially concentrically thereof'over a porti'oiiof'its' periphery, said drum being formed with an open magnetic circuit adapted to beclosed by the band, means for magnetizing said drum to increase the friction" between the druinand the" band fand thereby causeth'e band to be moved by the drum, and means for arranging a greater orless portion of the band in concentric relation with the drum;

4'. In an electric relay, the combination of a drum of magnetic material comprising a pair of flanged members having their flanged portions extending toward each other and spaced froineaclr other to pro- Vide an annular gap,'a second body of magnetic material l in frictional engagement therewith, a coil within the drum for magnetizing-said bodies to increase the friction between them and means] actuated," by

changes in the friction between said bodies.

5; In an electric relay, the combination of a. rotatable drum of magnetic material comprising a pair of flanged members having their flanged portions extending toward each other and spaced from each other 'to rovide an annular gap between them, a' hand of magnetic material in frictional engagement with said drum, said band being arranged substantially concentrically with the drum over a portion of its periphery and closing said gap, and a coil for magnetizing said drum to increase the friction-between the drum and the'band'and thereby cause the band to be moved by the'drum; V

6. In an electric relay, the combination of a rotatable drum of magnetic material comprising a pair of (flanged members having their flanged portions extending toward" each other and spaced from each other to provide an annular gap between them, a band of magnetic material in frictional engagement with the drum, and arranged to close said gap, yielding means for preventing movement of the'band due to its normal frictional engagement with the drum, and.

a coil for magnetizing said drum to increase the friction between the drum and the band and thereby cause the band to be moved by the drum. I

7. In an electric relay, the combination" of a rotatable drum of magnetic material forming an open magnetic circuit, a band of Cal magnetic material in frictional engagement with the drum, said band serving to close the magnetic circuit of the drum and extending substantially concentrically over a portion of its periphery, and a coil for magnetizing the drum to vary the friction between the drum and the band.

8. In an electric relay, the combination of a rotatable drum of magnetic material, a band of magnetic material in frictional engagement with the drum, a coil for magnetizing said drum, springs at the ends of the band for maintaining it in engagement with the drum, one of the springs acting to prevent movement of the band by the drum due to the normal friction between said elements and to permit movement of the band by the drum when the drum is magnetized by passage of current through said coil, and means actuated by movement of the drum.

9. In an electric relay, the combination of a rotatable drum of magnetic material, a band of magnetic material in frictional engagement with the drum, yielding means for preventing movement of the band dueto its normal frictional engagement with the drum, a coil for magnetizing said drum to increase the friction between the band and the drum and thereby cause the band to be moved by the drum, said yielding means being adapted to allow the band to be moved by the drum and acting to move said band in a reverse direction when the friction again decreases to normal and means actuated by movements of the band.

10. In an electric relay, the combination of a rotatable drum of magnetic material forming an open magnetic circuit, a band of magnetic material in frictional engagement therewith adapted to close the magnetic circuit of said drum, yielding means for preventing movement of the band due to its normal frictional engagement with the drum, and a coil for magnetizing said drum for varying the friction.

11. In an electric relay, the combination of a rotatable drum of magnetic material forming an open magnetic circuit, a band of magnetic material in frictional engagement therewith adapted to close the'magnetic circuit of said drum, yielding means for preventing movement of the band due to its normal frictional engagement with the drum, a coil for magnetizing said drum "to increase the friction between the band and the drum and thereby cause the band to be moved by the drum, said yielding means being adapted to allow the band to be moved by the drum and means actuated by movements of the band.

12. In an electric relay, the combination of a drum of magnetic material, a coil for magnetizing it, means for supplying current to the coil to vary the magnetization of the drum, a body of magnetic material engaging the drum, and polarizing means for said drum, said polarizing means being separate from said coil.

13. In an electric relay, the combination of a drum, a pair of coils within said drum, one of said coils being connected to a source of controlling current and the other to a local source of current, and a band engaging the drum.

14. In an electric relay the combination of a body of magnetic material, a second body of magnetic material in frictional engagement therewith, means for magnetizing said bodies from a local source of polarizing current and means for magnetizing said bodies from a source of controlling current for varying the friction between them.

15. In an electric relay a rotating drum of magnetic material comprising a pair of flanged members having their flanged portions extending toward each other and spaced from each other to provide an annular gap between them, a band of magnetic material in frictional engagement with the drum and magnetizing means for said drum connected with local source of current for polarizing said members and with a source of controlling current adapted to vary the friction between the drum and said band.

16. In an electric relay, the combination of two cooperating means connected to the same controlling arm, each of said means comprising a body of magnetic material, a second body of magnetic material in frictional engagement therewith and means for magnetizing said bodies for varying the friction between them.

17. In an electric relay, the combination of a pivoted arm, two cooperating means for actuating said arm, each of said means comprising a rotatable drum of magnetic material, a band of magnetic material and means for magnetizing said drum for varying the friction between the drum and the band, said drums being rotated in opposite directions.

18. In an electric relay, the combination of a pivoted arm, two cooperating means for actuating said arm, each of said means comprising a rotatable drum of magnetic material, a band of magnetic material and means for magnetizing said drum for varying the friction between the drum and the band, said drums being rotated in opposite directions and said magnetizing means acting in opposite directions to increase the magnetization of one drum and decrease the magnetization of the other.

19. In an electric relay, the combination of a pivot-ed arm, a pair of drums of magnetic material rotating in opposite directions, a pair of bands in frictional engagement therewith, connected to opposite sides of the pivot of said arm, means for preventing movement of the bands due to their w xl; fri ional; eQgag-em m w th he;-

mm iaind; cQil fmmagmtiz ng s drums, sand 0011s belng Wound so, that-- the magnetl zm ng: efiesstss ar qpposite- I ele tri rlay, the; emb na om f swatc member, a pair f c xial, d ums f, magmatic ma rial rat -tab e opposite i ;Qn$, a pairi of bands; in frictional n: gagement with said drums, said bands being effects are opposite.

' Q MAN M LAGHLANQ V 

